pickettt

I rode and raced a bonded aluminum Trek frame for 14 years. There were no problems.....that I could see, feel, or hear.

pickettt

This isn't true, but that's a long drawn out argument. Steel bikes have their place.

Sangetsu

Fashion is a fickle thing. Steel has always been a wonderful material for bicycles. Quality steels are light, resilient, absorb shocks and road imperfections really well. And steel is long-lasting, I have had old racers from the 1930's which ride as well now as they did when they were built.

But steel is not sexy. It doesn't need to be worked and formed into odd external shapes to improve strength and stiffness. Aluminum and carbon fiber frames can easily be formed into the sexy shapes that are popular with riders now. For the most part, the compact frame designs and sloping tubes are more cosmetic than functional. Kind of like the 70's Corvette sports car, with it's pointy nose, flared fenders, and sexy curves, it looked good, but it was actually significantly less aerodynamic than the boxy Chevette economy car.

Cannondale's engineers are quite brilliant people, and because of this, Cannonade has been the last of manufacturers to follow the current trend of sloping top tubes. Their engineers found that the old parallelogram design was the strongest and lightest form for a frame. But the market wants form more than it wants function. Even Cannondale had to succumb to the current trend if it wanted to sell bikes, and their newer models have the sloping design.

Let's face it, many people buy goods based primarily on their appearance. But the problem is that fashions change. What is "hot" today is "not" tomorrow. Steel bikes have been around for a long time. Manufacturers love the fickleness of fashion, it means riders will regularly exchange their old "uncool" bikes for the latest models.

Personally, having ridden bikes since the early 80's, I love the simple and elegant design of a steel road bike frame. It is not always the most fashionable kind of bike, but like Levis or Coca Cola, it never goes fully out of style. I like the smooth and supple ride of a good steel frame, and the fact that it can take scratches and dings with no consequences. What's more, my kids or my grandkids can enjoy the bike when they are old enough to ride.

I'm starting to build a new bike, as my current steel steed was made when Bill Clinton was president. So, I am getting a steel Cinelli Super Corsa, and building on that. I will have to use some carbon components, as all of Campy's high-end gear is not carbon fiber (when it comes to bikes and bike components, if it's not made in Italy, it's not for me; I too am somewhat fashion-conscious).

pickettt

......Steel Ritchey Breakaway Cross with Super Record
rit.jpg

Rcrxjlb

My 1993 Trek 1200 (aluminum frame, chromoly fork) seems pretty solid to me.

And I weigh 250 lbs...

drlogik 

Aluminum, steel and carbon bikes can and due fatigue; however, the shelf life of a steel bike if properly ridden and treated will last a life time. I was told by a reputable and very knowledgeable bike shop owner that aluminum bikes under normal riding conditions will last 5 to 10 years before they should be inspected closely. Steel he said would last almost indefinitely if maintained well. Carbon he said had the lowest shelf life and 5 years before they really need a full inspection.

He also carried no steel bikes because in his words, there is zero demand for them. He looked at me and said, "I'm a business man. I don't stock what I can't sell but steel is the way to go if you want longevity".

Headpost

Is this really true? I hate sloping top tubes just because I'm used to them being horizontal and sit on them sometimes--at red lights or coasting a short distance or whatever--so when they're at an angle it can be painful.

It's an old piece, using now-outdated frames for test subjects, but Sheldon Brown has an article posted on his site about high-end carbon fiber, aluminum, titanium, and steel frames that were subjected to a fatigue test by some German cycling magazine. I'm not allowed to post the link, but it's easy to find.

Basically the steel frames all failed first. Does this mean anything in the real world? Just--to me--that the "other" frame materials are perfectly legitimate, and the very real problem of breaking frames and parts is much more complicated than the question of which material they're made of.

kcblair

Please describe, what should be inspected closely, on an aluminum frame. Thank you. KB

drlogik 

All welded joints, dropouts, etc. Check for cracks, dents, peeling paint areas (could indicate a stress in the metal), etc. I do this on all of my bikes a couple of times a year. Usually done when I'm doing some maintenance anyway.

cyccommute 

There's a whole lot to unpack here. Let's start with the myth that steel is light, resilient and absorbs shocks. It doesn't and isn't. Steel has a density that is 3 times that of aluminum. Steel is stiff and, as with any stiff material, will transmit vibrations readily.

Aluminum, on the other hand, is light and, because it is a soft material, doesn't transmit vibration at all well. You could play a guitar with steel strings but not with aluminum ones.

When used in a bicycle frame, steel has some of the qualities that people like because of the way the material is used but not because of what the material is. Steel tubing has a small cross-section and can bend rather easily. Aluminum tubes made to the same diameter as steel ones make for a bike that is basically metallic pasta. Alan bicycles with "conventional" but very thick walled tubing from the 70s and 80s were not known for being stiff bikes. If steel bikes were made using the same tubing size as aluminum bikes currently use, the result would be a ride harsher than any aluminum bike ever made.

"Sexiness" has nothing to do with either aluminum's or carbon's usage in bicycle frames. It is driven by weight and economics. In the early days of aluminum's introduction, steel frames outweighed aluminum significantly. In the touring market where steel bikes are still used overwhelmingly, steel bikes bikes weigh significantly more than the only aluminum offering. A Surly LHT weighs in from 30 to 35 lbs while a Cannondale touring weighs in at less than 30.

Carbon has supplanted aluminum for the same reason...weight.

All the tube forming and frame designs are done to improve the ride characteristics of the frame but they aren't done strictly...or even mostly...for looks.

Your statement makes zero sense. A smaller triangle is less flexible and uses less material. Less material means a lighter bike. Cannondale used sloping top tubes on their mountain bikes almost from inception of that line to provide a stiffer frame and lower standover.

I suppose you could say that their 2003 bikes are "newer" models but 14 (almost 15) years of sloping top tubes isn't "new" in my book.

"Looks" has little to do with bicycle purchases. Innovation is what drives bicycle sales and improvements. Mountain bikes with front shocks supplanted rigid mountain bikes because they are a vast improvement over the previous bikes. Full suspension supplanted front suspension because the bikes work better for the task at hand. Aluminum supplanted steel because it is lighter and the rider can go faster. Carbon is replacing aluminum for the same reason.

Whatever floats your boat but, just like the rotary phone, dial-up modems, Commodore 64s and platform shoes, steel has been replaced by something that performs better. My kids and grandkids can find their own bikes when they want to ride something. Mine probably won't fit them anyway.

cyccommute 

Just look for cracks in welds. But, honestly, don't be obsessive about it. Aluminum does not fail the way most people will tell you it does. It is soft and tends to tear rather than shear. Steel is hard and stiff so it fails exactly the way that most people think aluminum fails.

In my experience...2 broken aluminum frames and 2 broken steel frames plus numerous broken steel and aluminum parts...aluminum will creak and groan prior to failure while steel gives no warning. Steel just goes "ping" and it's broken.

kcblair

Thanks for the info. I recently got my first aluminum frame. All other bikes are steel, never any issues. KB.

Jean_TX

To Cyccommute : Thanks for presenting the facts about materials versus the usual "steel is real" myth !

pickettt

This is the pertinent piece of information. Regardless of the characteristics of the raw materials, as it pertains to bicycles, steel frames are more compliant than aluminum frames.

gemini

Incidentally I've recently seen cyclist Youtubers / video bloggers suffer those two frame failures, but on steel bikes. One was a vintage steel road bike, whose downtube snapped completely at the downtube shifters, the other a recent Surly fatbike, whose chainstay snapped in two. That one was on tour in a country foreign to the rider and he had to find a welder in the nearest town. So, on your anecdotal evidence and mine, it's 50-50 aluminum-steel

What I was impressed by in those videos and other instances of frames breaking, is how often it doesn't cause an accident. The tourist with the snapped Surly chainstay actually didn't even realize it for quite some time and thought the knocking sound was coming from his crankset and kept pedaling. The snapped downtube I thought would be a guaranteed recipe for disaster, especially since the shifters were above the point of failure, so the cables would be yanked once the tube was broken, but no, the rider just felt the bike lose rigidity and stopped.

broken foot

years ago, in netherlands, a friend sold me his old aluminum gazelle, the classic steel models at the time were actually more expensive or very abused.
i liked the bike alot and had it shipped home. since then it has been used to commute and also during weekend.
the bike already had tousands of miles when i bought it and i should have put another 8-10k on it, many of those miles has been ridden on rough tarmac or cobblestone. i also own a vintage steel bike, previously had a cheap steel rubbish bike, i rode a very good Fahrrad Manufaktur and a proper dutch steel bike. and my experience is:

-the aluminum gazelle is just as heavy as the steel dutch and the manufaktur, they all have identical/similar dimensions and accessories, so weight factor of the frame is not that important on the complete package (20kgs +-).
-i could feel no difference in stiffness between my alu gazelle and the steel dutch or the VSF
-my vintage bike (around 1965) is lighter and seems less stiff, but 50 years explain the difference and tubes are really small diameter.
-the cheap steel bike i owned did seem less stiff but could be just an impression caused by the bad fittings of the central movement, handlebar and saddle. was also a bit lighter but the difference was caused by rubbish components, not the frame.

so my point is this: with an average use of the bike the alu frame will last more than you need, it's overbuilt so probably all the other components will fail first.
if you do downhill you could break the alu frame but also the steel or carbon one.

i like the look of the steel frame bike and the idea it could last a really long time but it can rust, also it can be made less durable if you try to save weight on it (reduced thikness and risks of bending tubes)

Tape2012

I remember reading that an aluminum frame purely designed to meet strength requirements would result in portions of the frame being so thin that it would dent very easily so the frame ends up being overbuilt and stiff. But aluminum will fatigue. And both will oxidize.

I think there are some misconceptions about CF. Compared to steel and aluminum, CF can be made much stronger and impact resistant than either. Just consider how much CF is used in the aerospace industry. I have seen CF helicopter rotor blades take a bird strike where a softball size hole was punched into the blade and the helo landed safely. Plus the blade was repaired and returned to service. Compare those forces to what a bike frame would see.

I understand CF bike frames are not made to the same standards as helo blades, just offering my perspective on what CF is capable of.

The other attractive quality of CF is that it doesn't fatigue. Also if the paint is intact, UV degradation is not an issue. A well built CF bicycle should have a service life that is much longer than the person riding it.

broken foot

carbon fiber can be expensive to repair, i have a good experience with composite materials in kayaks and boats. sea kayaks are overbuilt and easy to repair thanks to their shape. a race CF ultralight kayak is very easy to break and very difficoult to repair.
the longevity/resistance depends on how the material is used.
polyethilene is a cheap plastic with low performance but in the boat rent i usually choose a old plastic DAG wich is still perfectly functional.

bike frames are more complex than boats because there are junctions and tubes with small diameters and also on a race frame weight is more important than longevity.
the same is true for steel, if you overbuild it then it will outlast the owner, if you try to make it ultralight it probably will break.

alu frame are always overbuilt to some degree, the optimal thikness for aluminum is so small that can't be used because the smallest impact would bend the tube.
if you put on a scale the alu frame and a butted steel one i bet the difference is minimal. fact is that the butted steel costs more to manufacture.

Tape2012

I can't disagree with anything you have said. If bike frames were laid up and inspected to the same exacting standards and used the same materials as aerospace components they would be light and almost indestructible but would cost a fortune. Plus as you've said frame builders put weight over service life. In the long run it's probably more cost effective to build them cheap and replace when necessary.

It's unfortunate because it gives CF a reputation among cyclists that it really doesn't deserve.

cyccommute 

It's not just carbon fiber. Every frame material (or car body material) that isn't steel is "going to shatter" like glass in a crash. Aluminum "fails catastrophically!", magnesium (used in only a few bicycle frames) will "burst in to flames!", fiberglass car bodies (i.e. Corvettes) are going to "explode!" at the slightest impact as are carbon fiber bikes.

All of these are myths perpetrated by people who have no idea of the materials properties. Aluminum isn't a brittle. It's soft and it cracks and tears rather than shear. Magnesium will burn but it takes a lot of heat to get it going. Carbon fiber and fiberglass are fibrous materials that resist shearing. They are more like wood and trees than metals.

Oddly, the one material that doesn't seem to "shatter" is titanium. It has it's problems...it's soft and it work hardens and it can crack...but I've never read anyone poopooing it like they do aluminum and carbon.

I have broken both steel and aluminum frames and parts. The failure mode that I've experienced overwhelmingly for aluminum is a slow breakage with lots of warning beforehand...creaking and groaning...before I notice a crack. Steel frames and parts, on the other hand, just go "Ping!" and are broken. Steel breaks much more like what people expect from aluminum. It really does just "shatter" without warning.

Tape2012

Agreed. That property of aluminum makes is definitely an advantage in aerospace and should be in bike frames as well. Aluminum gives plenty of warning before failure where most other materials do not.

prathmann

Put some miles on either an old Vitus or Alan aluminum frame and get back to us. Both of these were far more flexible than any steel frame I've ridden.

Korina

Can someone clarify this for me? I thought aluminum frames were actually an alloy. Wouldn't whatever it's alloyed with affect the performance of the frame?

Fascinating conversation, BTW.

cyccommute 

"Aluminum" and "alloy" are used interchangeably. Most people don't make a lot of distinction between the two major aluminum alloys...6061 and 7005. Yes, which one is used has some affect on the performance but the differences are relatively minor. Most of the differences are in the manufacturing of the frame.

"Alloy", by the way, applies to other metals as well. An alloy is simply a solid solution...think salt in water or sugar in tea. Steel is an alloy of various things based on the properties. In actuality, "iron" is seldom pure and is alloyed with carbon as part of the process of turning iron ore into iron. Titanium is alloyed with various other metals to make it easier to work with.

But, for the most part, people say "alloy" when they mean "aluminum alloy".

velojym

I know this thread has gathered a little dust, but I'll leave this here for those who are interested.


https://www.sheldonbrown.com/rinard/...tigue_test.htm